I am using chia seeds and I am fixin' to go back to flax seed. Mostly because I saw no difference and since I can get flax cheàper, I'm going back to it. I have used chia seeds since September. When I say no difference I mean they looked the same as when they were on flaxseed. Also none of my are allergic to flax.
Sorry no help on your question, but you did give me a needed giggle today. All I could think of was "Chia Pets" - you know ch- ch- ch- chia, and horses sprouting funky grasslike hair.
My sister put her whole herd on chia seeds. She said she didn't see any difference in any of the horses. She switched everyone over to forco recently. I'm feeding (finishing up a tub of a flax/chia supplement I got from horsetech. Can't say if I noticed a huge difference my boys are just now starting to shed their winter coats. I'm not sure if I'll get another tub or not, I got the big 25lb tub.